1. Field of the Invention
The present invention relates to a regenerator and a cryocooler using the same, and more particularly, to a regenerator and a cryocooler using the same capable of improving regeneration performance of storing heat included in a working fluid and transmitting the stored heat to the working fluid and of minimizing a weight.
2. Description of the Background Art
In general, a cryocooler is mainly used to cool small electronic components, superconductors or the like. As the cryocooler, there are a Stirling cycle cooler, a pulse tube cooler and the like.
The cryocooler includes a high temperature part for generating heat while compressing a working fluid by converting electrical energy into kinetic energy; and a cooling part rapidly cooled by a working fluid which is expanded by a pulse difference of the compressed operation and absorbs external heat. And, a channel through which a working fluid flows between the high temperature part and the cooling part is formed, and a regenerator including a thermal energy storage material exchanging heat with the working fluid is mounted at the channel.
That is, in a process that a working fluid flows from the high temperature part to the cooling part, heat included in the working fluid is absorbed by the regenerator, and thus the relatively-low temperature working fluid flows to the cooling part. In addition, in a process that a working fluid flows from the cooling part to the high temperature part, the working fluid receives the heat absorbed by the regenerator, and thus the relatively-high temperature working fluid flows to the high temperature part.
Accordingly, when a working fluid flows from the high temperature part to the cooling part, the regenerator has to absorb heat included in the working fluid as much as possible. In addition, when a working fluid flows from the cooling part to the high temperature part, the generator has to transmit heat to the working fluid as much as possible. According to those, efficiency of the regenerator is determined, and the efficiency of the cooler greatly affects efficiency of the cryocooler.
Many researches are ongoing in order to improve heat exchange efficiency of the regenerator. As a thermal energy storage material of the regenerator, a lamination body formed by laminating a plurality of meshes having fine holes is used, or a pressed stainless lump (cotton-shaped) made by lumping a fine stainless fiber is used. Of them, the stainless lump is frequently used because it has better efficiency than the mesh laminated body.
However, the regenerator using the stainless lump or the mesh laminated body is very heavy. In general, because the cooling part of the cryocooler comes into a cryogenic state in operation, lubricating oil freezes and thus cannot be used, and therefore a fluid bearing is used. For this reason, in case that a heavy regenerator of the cryocooler makes a relative motion, abrasion occurs at the regenerator and a component which makes relative motion with the regenerator, thereby deteriorating reliability and consuming a large amount of operation energy.